<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="./css/bootstrap.css">
    <style>
        .box {
            height: 100px;
            width: 100px;
            background-color: aqua;
            margin-bottom: 20px;
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="row">
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>
            <div class="col-xs-12 col-sm-6 col-md-6 col-lg-4">
                <div class="box"></div>
            </div>


        </div>
    </div>
</body>

</html>